Voice communication systems are susceptible to non-speech noise. One source of such noise can be environmental factors, such as transportation vehicles. This noise typically enters the communication system through a microphone used to receive voice sound. To improve the quality of the speech communication, efforts have been made to eliminate the undesired noise.
One type of noise suppression which uses band pass filters to remove noise at specific frequencies is described in U.S. Pat. No. 5,432,859 entitled “Noise-Reduction System” issued Jul. 11, 1995 to Yang et al. A system which reduces noise using spectral subtraction is described in U.S. Pat. No. 5,610,991 entitled “Noise reduction System and Device, and a Mobile Radio Station” issued Mar. 11, 1997 to Janse. Further, a system which used power spectral subtraction is described in U.S. Pat. No. 5,668,927 entitled “Method for Reducing Noise in Speech Signals by Adaptively Controlling a Maximum Likelihood Filter for Calculating Speech Components” issued Sep. 16, 1997 to Chan et al.
These noise suppression systems do not provide for amplification of specific frequencies of the voice signals prior to performing an adaptive noise suppression operation. For the reasons stated above, and for other reasons stated below that will become apparent to those skilled in the art upon reading and understanding the present specification, there is a need in the art for alternative noise suppression communication systems.